Integrated sorption and diffusion model for bentonite. Part 2: porewater chemistry, sorption and diffusion modeling in compacted systems
Integrated sorption and diffusion model for bentonite. Part 2: porewater chemistry, sorption and diffusion modeling in compacted systems
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膨润土的综合吸附和扩散模型。
DOI：
10.1080/00223131.2014.914453
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发表时间：
2014
影响因子：
1.2
通讯作者：
M. Ochs
中科院分区：
文献类型：
--
作者：
Y. Tachi;K. Yotsuji;T. Suyama;M. Ochs
重要的是要了解的耦合过程的吸附和扩散的放射性核素（RNs）在压实膨润土，并开发机械模型，可以帮助预测的长期性能的地质处置系统的放射性废物。基于粘土-水相互作用、吸附和扩散模型的一致性组合，建立了吸附和扩散集成模型（ISD）。基于双电层理论描述的相对离子浓度和粘电效应在带负电荷的粘土表面的扩散模型耦合与孔隙水化学和吸附模型。该ISD模型成功地测试了各种锕系元素与复杂的化学（Np（V），Am（III），U（VI）的条件下，形成带电荷的碳酸盐络合物）在第1部分中考虑，通过使用已公布的扩散和吸附数据（Da，De，Kd）作为部分蒙脱石密度的函数。定量协议，观察考虑孔隙水化学和占主导地位的水物种的不确定性。因此，可以得出结论，ISD模型是能够充分解释的吸附和扩散行为的各种RNs在压实的蒙脱石具有复杂的化学。所进行的建模表明，不确定性主要与孔隙水化学和RN形态，这些参数需要仔细评估。
It is important to understand the coupled processes of sorption and diffusion of radionuclides (RNs) in compacted bentonite, and to develop mechanistic models that can aid in the prediction of the long-term performance of geological disposal systems of radioactive waste. The integrated sorption and diffusion (ISD) model was developed based on the consistent combination of clay–water interaction, sorption and diffusion models. The diffusion model based on the electrical double layer theory describing relative ionic concentrations and viscoelectric effects at the negatively charged clay surface was coupled with porewater chemistry and sorption models. This ISD model was successfully tested for various actinides with a complex chemistry (Np(V), Am(III), U(VI) under conditions where variably charged carbonate complexes are formed) considered in Part 1, by using published diffusion and sorption data (Da, De, Kd) as a function of partial montmorillonite density. Quantitative agreements were observed by considering uncertainty in porewater chemistry and dominant aqueous species. It can therefore be concluded that the ISD model developed here is able to adequately explain the sorption and diffusion behavior of various RNs with a complex chemistry in compacted bentonites. The performed modeling indicates that uncertainties are mainly related to porewater chemistry and RN speciation and that these parameters need to be carefully evaluated.